Fig 3. Syk-ERK/JNK pathway regulates inflammasome activation in response to H. capsulatum.

(A) Wild type BMDCs were stimulated with or without (0 min) H. capsulatum for 10, 20, 40, 60, and 120 min. Cell lysates were subjected to Western blotting for detection of phosphorylated Syk, JNK, ERK and p38. (B, C and D) Fetal liver-derived dendritic cells from wild type, Syk-deficient and Syk heterozygous fetuses were stimulated with H. capsulatum for (B) 20 minutes and (C and D) 18 h. Stimulation by LPS plus ATP (L+A) was used as a positive control for IL-1β induction (E and F) BMDCs were pretreated with ERK inhibitor (U1026), JNK inhibitor (SP600125) and p38 inhibitor (SB203580) at 10 μM for 1 h before stimulation with H. capsulatum. (C and E) Culture supernatants were collected and quantified for IL-1β by ELISA (n = 3–5). (B, D and F) Cell-free supernatants and cell lysates were analyzed for inflammasome components by Western blotting. β-actin was used as an internal control. Error bars indicate standard deviation of the mean. One representative of three (A, C, D and E) or two (B and F) independent experiments is presented. * p < 0.05, ** p < 0.01 [2-tailed t-test (C); one-way ANOVA with Tuckey post-hoc analysis (E)].